Fast-speed tractor



Feb. 21, 1928.

'W. H. SMYTH FAST SPEED TRACTOR QuE..

INVENTOR WITNESSES #LU/1W j @f4/1M.

Patented Feb. 21, 1928.A

PATENT OFFICE.

WILLIAM H. SMYTH, OF BERKELEY, CALIFORNIA.

FAST-SPEED TRACTOR.

Application led March 1v1, 1924. Serial No. 698,437, v

This invention relates to. vehicles forA load bearing and motor service. It has for its main object to provide a wheel-assembly for vehicles that will permit of faster speed than is practicable under present practice and construction in the track-layer form of tractors, and, incidental to the main purpose, to provide in a vehicle of the track-layer type, a chain-trackassembly with an irreducible minimum of load-bearing rotative parts without diminution of effective ground contact or wheel-base, but a substantial reduction of over-all length of chain-track-assembly, and by these and other means to effectV a corresponding reduction of weight, cost, wear-and-tear and upkeep expense, with simplification of construction and ease of replacing worn parts.

Atypical expression of my invention, that accomplishes these objects is illustrated in the accompanying drawing, wherein:

- Fig. l' shows a side elevation of those parts of a tractor most directly affected by my nvention;

Fig. 2 shows a section of F ig.'1 on the line of .Q3-fc; i

Fig. 3 shows a side eleva-tion of the wheelassembly with the track-layer chain-track in place; l Fig. 4. shows a section of Fig. 3 on the line 0f .f/-y- In the track-layer tractor art, heretofore, twol'ines of inventive development have been followed, resulting in two types of devices. In one the track is stationary with reference to the framework; in the other it travels` with and is Apart of the chain, as an endless chain-track.

Both of these types are erroneously constructed, showing failure to realize theta track-layer tractor is essentially a traveling cog-railway that lays its cogged-track as it progresses. Thus, in the first or roller-chain type, the load-bearing wheels, being journaled on the endless chain, must of practical necessity, be small' in diameter. They are, in practice, mere antifriction rollers. l the small' diameter of these chain-carried rollers, their rotative speed must necessarily be high compared to the speed of advance of the whole machine, and' doubly so in the upper reach of the chain. Also this form inherently involves great multiplication of rotative and friction generating parts'with corresponding difficulty of lubrication,

And byr The second or chain-track type while avoiding some of the troubles of the first, has inherent limitations, made apparent in the slow speed, the heavy upkeep expense, and the characterizing construction of the now familiar tracklayer tractor.

A `cogged-railway, laying its own track as it advances, involves twodistinct func tions which must be equally provided for in order to realize an eflicient machine: laying a smooth track, and bearing the weight of the motor element andy other load.

Each of the types mentioned vis based upon and provides effectively for only one of these functions; thus introducing a different law of operation in two machines designed to accomplish the same purpose.

In the first type, a smooth continuous track is provided atthe costv of the load bearing function. This is seen in the nec essarily small diameter of the chain-carried rollers.

In the second type the'load'bearing` function is provided for by the relatively large truck-wheels stationary with reference to the frame, but at the expense of the track function. The track is necessarily rough as it buckles between the peripheries of the loadbearing wheels; also it vibrates excessively in the upper (fast traveling) stretch, except at slow speed of advance.

I deem the foregoing necessary to a proper understanding of the present invention in which the track-laying function and the load-bearing 'function are independently provided for without compromise or loss to each other; and in which the construction partakes more of the round-wheeler construction than of that of the customary tracklayer tractor. And thus I am enabled i to provide a fast-speed tractor that embodies and combines the tractive capability of the cogged-railway with the speed capability and other advantages of the automobile and track locomotive.

As the wheel-assembly alone distinguishes thev tracklfaying type from the round-wheel'- er7 form of vehicle, the mot-or element and its framewrokbeing common to both types, and the constructionof these parts being within the knowledge of mechanics skilledI in the art, I willconfine my description to those parts of the complete structure directly affected by my invention. But, in what follows, it is to be understood that the power?- wheel with its ournal-boxes and frame herein shown and described, are intended to represent not alone a power-wheel and wheelassembly frame, but also, for the purpose of this disclosure, the motor-element complete with suitable rigid, flexible, or resilient con nection between the power-element-frame and, the wheel-assembly that is described and illustrated herein. And further, that a similar wheel-assembly is or may be, on the opposite side of the inotoror main-frame of the completed machine. l

lilith this understanding, A, represent-s framework pertaining to a vehicle. In the present expression of my invention it is preferably constructed of longitudinal bars 0r tubes a-al-ag-a, upon which is ,heatshrunk or otherwise secured brackets A1- A'2'-A3, the side members of frame A, being securely tied together by heavy brace-rods Att-A5 A, in substantially the same horizontal plane as the power-wheel shaft. rlhe frame A., carries journal-box C, and shaft l5, journaled therein. Upon the shaft B, is secured power-wheel D, withY its circumferential teeth or sprockets. Upon the brace-rod A, is hinged a curved upper guide-rail E, and also a curved lower guide-rail F. The guide-rails E and F, extend rearwardly from theirhinge connection toward and close to of a caliper about to caliper the power-wheel. rllhe guide-rails E and F, thus constitute with the power-wheel D, an oval substantially continuous guide-way. y

Trained around the guide-way is an endless track-chain G. It is preferably formed of parallel links (/-rf/, constituting` an end less, double-track rail or twin-track. rlhe rail is provided' with laterally extended tread-shoes H, adapted to afford a wide grouml-bearing support for the machine. On the links of the chain G, intermediate of its track surface and its ground-contact-surface are journaled antifrietion rollers I,

ada lated to roll uion the 0'uide-rail E-F y and coact with the power-wheel D, to'forin abutments therefor. I

Fivoted on the brace-rod A5, is a journalarm J, extending rearwardly, and upon its ren'ward end is journaled a shaft K of twinwheelsVV L-Ll, travelable upon the twintracks gulf/1. Pivoted upon the same shaft is a similar journal-arm J1, extending forwardly.y similarly provided as is J, with a shaft K1, and twin wheels L2-L3. This pair of unit-twin-wheels lr-Ll, lig-L3, constitutes the supporting wheels of the machine, they are preferably flanged; and they are preferably of greater diameter than the power-wheel D. Extending` downwardly frein each journal-arm J-J1, -pivoted respectively at m and m1, is a strong link hlt-M1. as shown in Figs. l. 2 and 4. The lower .ends of the links lil-M1, are pivotally secured to the lower guide-rail F, at f-f, respectively, as best shown in Fig. l. VFrom a point adjacent to f1, and extending to its end, as shown in the same figure, the lguiderail F, is preferably laminated for resilient lexibility. Directly above the brace-rod A?,

another brace-rod A4, and upon it is centrally pivoted a strong rocking-arm N of substantially the same length as the combined lengths of the journal-arms J J1, so that one end of the rocking-arm is above the end of the journal-box of the journal-arm J, and its other end above that of J1, and a coil spring j, is interposed between the journal-arm J, and the rocking-arm at one end while a similar spring is interposed between J1,'and the otherv end of the rocking-arm. Suitable cups f1a-a1 and (f2-ji are provided on the rockingarm and the journal-arn'is J-Jl, to receive and position the springs j jl, all of which is clearly shown in Fig. l, and further illustrated in Fig. 2 and Fig. 3.

Centrally located of the two sides of the frame A. and of. the bracket A2, and resting 'thereupon in a spring cup at, is a third coil spring e, its upper end abutting the under side of the upper guide-rail E, in a suitably disposed springl cup el, secured to the guide rail E, all of which is best shown in Fig. l,

rand. further illustrated in Fig. 1l. the power-wheel D, like the hinged members By means of .the construction` herein set forth, the load on the track-assembly is borne upon the twin-wheels'LQLHLL-L, the antifriction. rollers l, serving merely to facilitate the travel of' the track-chain G. ln Fig. 1, it will be noted that the rollers marked I-I, immediately beneath the bearing-wheels L1. L, do not contact with the under side of guide-rail F. This is also clearly shown in the ysection Fig. 2, by the space between the roller I, and the under side of guide-rail F. lVhen traveling upon uneren `,rroimd, overa hununocl, the wheels 'r Yr ifi-f, .lf-L2 still bear the load and onlyV such pressure and duty falls upon the rollers I, I, between the 'peripheries'o't' the bearing-wheels as is due tothe resilience of the guide-rail F, and this duty isdistributed over all the intervening rollers I, with only such pressure as is desirable to ensure tractive contact of the tread shoes Hell, with the ground surface,betweenthe peripheries of the load-bearing-wheels.L-Ll, L2-L3.

The independent pivotal mounting of each twin-wheel unit permits them to respond independently of each other: and the equalizer rocking-arm N, with the interposed springs y' and y, give resilieutly flexible adjustment of the guide-rail F. to any ground unevenness while n'iaintaining the track-chain G, in smooth undulations withoutv the stresses and torsions due to buckling of the chain G, between load-bearingwheel peripheries.

The travel of the track-chain G, in' its upper stretch, and around the oval of the lll() guide-way is smooth, as `each link is carried on' its antiiriction roller. i e i llilith the arrangement shown and de# scribed herein, thoughY each track-assembly has in eflect but two points oli support, the wl'icelbase is as long is customary in tracklayers having live or sixy truck-wheels. The absence of the ordinary chain-track idlerwheel makes thev length of the track-'assembly shorter (by the diameter of such idlerwheel) than the ordinary tracklayer tractor, with a corresponding savingofv weight, cost and upkeep expense; which is one of the objects of this invention. Y

rlhe construction herein described and illustrated', with the axes ofB, K, A'KIT and A6, all located substantially inthe sarnc horizontal plane permits the load-bearing wheels to be oi relatively large 'diameter and oi greater diameter than that of the powerwheel D of normal size. This arrangement facilitates fast speed, and at the saine time raises the points of lubrication and the pow,- er-wheel out of proximity to the dirt and dust of the-ground. The ovalv guide-way not only tensions the 'track-chain but also furnishes a substantially continuous smooth track for the antifriction rolle-rs on fthe chain. This arrangement makes available as a source of economy thehigh speed ot Athe upper fold of the chain, heretofore ydetrimental, as its momentum and centrifugal action tend to lighten the pressure on the antilirietion rollers and guide-way. These va-rious constructions, ar angements 'and provisions facilitate high speed of chain-'track and fast speed oi advance-in the thus constructed machine, which is kthe prime object of the invention. n

ln view of these radical and pioneer' departures 'from present accepted practice and construction, I do not desire to be limited to the particular expression of my invention used herein for illustrative purposes, nor'to Vbe limited in any other way than in accord with a liberal interpretation and the reasonable purport ot the claims which follow.

I claim:

l. A vehicle comprising a frame, a powerwheel journaled thereon, an endless-chaintrack adapted to ground support, a support wheel travelablc uponv the ground run of the chain, an arm pivotedly connectedto the frame on which the support wheel is jourualed, the axes of t-he power-wheel and support wheel and pivotal connection being normally in substantially the same and their lowermost arcs in different horizontal planes.

Q. A Vehicle comprising a frame, a power'-v wheel journaled thereon,V an endless-chain twin-track ladapted to' ground support, twin support-wheels travelable upon the ground run of the twin-track, an arm'p'ivotally connected to the frame on which Vthe twin support-wheels are journ'aled, 'the aires et 'the power-wheel andsupport-wheels and pivotal connection being normally Ain substantially the same horizont-al plane.

3. A'vehicle comprising a traine, a powerwhecl journaled thereon, a. guide-rail pivotally connected to the frame, an endless-chaintrack trained around the power-wheel anti guide-rail, twin support-wheels Vtravelable uponl the ground run oi the chain, an arm pivotally connected to the viframe on which the twin support-wheels are jourualed`r the axesv of the power-wheel and support-wheels and thc pivot of the journal arm being normally in substantially the saine horizontal pla-ne.

il. A vehicle comprising a frame, a powerwheely journaled thereon, a guide-rail loru' ed ofupp'er and lower curved members pivotally7 connected to the frame, an endless-chain track trainedv around the power-wheel and guide-rail, twin support-wheels travelable upon the ground' run'oi' the chain, an arm pivot-ally connected to the :trame onywhich the twin support-wheels are journaled, the axes ofthe power-wheel andv support-wl'ieols and pivot oi the journalarm being normally in substantially the same horizontal plane.

,5, A vehicle comprising a frame, a powerwheel journal'ed thereon, a guide-rail formed 'efspring-controlledy upper and lower curved members pivotally'connected tothe frame, an endless-chain twin-track trained around the power-wheel and guide-rail, spring-opposed ysLuaport-wheels trave-liable upon the ground 'run of the chain, an arm pivotally connected to the frame on which the support-wheels are journaled, the aXes of the power-wheel and support-wheels and pivot `of the journal arm being normally in` sub-- stantially the same horizontal plane.

6. A vehicle comprising a rame,an endless cha-in track with antifriction rollers journaled thereon, means adapted to maintain the upper and lower run of the track in t-he same vertical lplane of travel, a support wheel travelable upon the ground run oil the chain, an arm lpivotally connected to the iframe on which the wheel is journaled, [a

second support-wheel similarly journaled on a second arm similarly connected to the frame,- and a guide-rail bridging the space betweenr the peripheries of the supportwheels vertically .movable therewith adjacent to the lower run of the track and coacting with the antifriction rollers on the rchain to control its tlexure.

- 7. A vehicle comprising a frame, an endless-chain' track with anti'friction rollers j'ournaledthereon,means adapted to maintain the upper and lower run of the 'track Iin the same vertical plane of travel, an arm pivotally connected to the trarne Aby one oi its ends, a spring-opposed support-wheel at the other end ofthe arin travelable on the grew-tlltll? the Chain, e second. indenni@ lll;

lll)

ently spring-opposed support wheel similarly journaled on a second arm similarly connected to the frame, a guide-rail bridging the space between the peripher-ies of the supportr wheels vertically movable therewith adjacent to the lower run of the track coacting with the antitrietion rollers on the chain to control its tlexure. p

8. A vehicle comprising a frame, an endless-chain track with antifriction rollers journaled thereon, means adapted to maintain the upper and lower run of the track in the same vertical plane of travel, an arm pivotally connected to the trame by one ot its ends, a spring-opposed support-wheel j ournaled at the other end oit the arm travelable on the Lround run ol the chain, a second independently spring-opposed support wheel similarly journale-d on a second arm similarly connected to the trame, a guiderail bridging," the space between the periphcries ot the support-'wheels vertically movable therewith adj acentvto the lower run of the track coacting` with the antitriction rollers on the chain tocontrol its tlexure, and a rock-arm pivoted to theirame above the journal arms in spring-controlled abutment therewith.

9. In a tracklayer tractor track-assembly,

"f'f a trame, .an endless-chain twin-track, two

sets oit twin support-wheels longitudinally spaced apart to constitute the wheel-base of the assembly, a separate radially movable journal-arm tor each set of twin supportif wheels pivoted on the trame intermediate sets of twin support-wheels longitudinally spaced apart to constitute the wheel-base of the assembly, a separate radiallymovable spring opposed journal-arm for each setof twin support-wheels pivoted on the iframe intermediate ol' the support-wheels.

12. In a tracklayer vehicle a track-assembly, a frame therefor', an endless-chain twintrack, two sets of twin support-wheels longitudinally spaced apart to constitute the wheel-base ot the assembly, a separate radially movable spring-opposed journal-arm Jier each set ot twin support-wheels pivoted on the frame in, substantially the same plane as-the normal horizontal diameters of the support-wheels. j

13. In a tracklayer vehicle track-assembly', a frame :tor the assembly, an endless-chain twin-track, two sets of twin support-wheels longitudinally spaced apart to constitute the wheel-base of the assembly, a separate radially movable journal-arm 'for each Set of the twin support-wheels pivoted on the trame intermediate ot the support-wheels, and a guide-rail bridging` the space between the peripheries of the support-wheels .vertically movable therewith adjacent to the lower run of the track coacting therewith to control its iiexure.

14. In a tracklayer vehicl-e track-assembly, a trame for the assembly, an endless-chain twin-track with antitriction rollers j ournaled. thereon, two sets ot twin support-wheels longitudinally spaced apart to constitutethe wheel-base of the assembly, afseparate radially movable journal-arm for each set of twin support-wheels pivoted on the frame intermediate of the support-wheels, and a guide-rail bridging the space between the peripheries ot the support-wheels.vertically movable therewith .adjacent to the lower run ot the track coacting with the antitriction rollers on thechain to control'its tlexure.

15.r In a tracklayer vehicle track-assembly, a frame Vtor the assembly, an endlesschain twin-track, twosets ot twin supportwheels longitudinally spaced apart to constitute the wheel-base ofthe assembly, a

Btl

separatecradially movable journal-arm ior each set of twin support-wheels.pivoted on the frame in substantially the same plane as the normal horizontal diameters ot the support-wheels, and a guide-railbridging the space between the peripheries o'f'tlie support-wheels vertically movable therewith adjacent to the lower run of the track coacting with the antitriction rollers on the chain to control its tlexure. 'j

16. In a tracklayer vehicle track-assembly, a frame 'for the assembly, an endless-chain twin-track, two sets ot' twin support-wheels longitudinally spaced apart to constitute the wheel-base ot the assembly, a separate radially movable spring opposed journal-arm for each set ot twin support-wheels pivoted on the frame intermediate of the supportwheels, and a guide-rail bridging the space. between the peripheries of the supportimi' wheels vertically movable therewith adja- I cent to the lower run. or' the track coacting with the antitriction rollers on the chain to control its tlexure. Y Y

1T. In a tracklayer vehicle track-assembly, a Aframe for the assembly, an endless-chain twin-track, two et twin support-wheels longitudinallyspaced apart to constitute the wheel-base ot the assembly, a vseparate radially movable spring-opposed journal-arm tor each set ot twin support-wheels pivoted' on the trame in substantiallyV the same plane as the normal horizontal diameters of the support-wheels, and a guide-rail bridging the space between the peripheries of the support-wheels vertically movable therewith adjacent to the lower run of the track coacting with the antifriction rollers on the chain to control its leXure. i

18. In a tracklayer vehicle track-assembly, a frame for the assembly, an endless-chain twin-track, two sets of twin support-wheels longitudinally spaced apart to constitute the wheel-baseof the assembly, a separate radially movable journal-arm for each set of twin supportwheels, a rocker-arm pivoted to the frame, and springs interposed between each journal-arm and rocker-arm to independently cushion the load on each twin support-wheel. i

19. In a device of the character described a load equalizer comprising a frame for the device, twoV unit support-wheels each unit wheel journaled on a separate radial vertically movable arm pivoted on the frame intermediate of the unit wheels, and a rockarm pivoted on the frame adapted to resiliently oppose the vertical movement of the support wheels.

20. In a device of the character described a load equalizer comprising a frame for the device, two unit support-wheels each unit wheel journaled on a separate radial vertically movable arm pivoted on the frame in substantially the same plane as the normal horizontal diameters of the support wheels, and a rock-arm pivoted on the frame adapted to resiliently oppose the vertical movepment of the support wheels.

22. In a vehicle, a frame, an endless chaintrack with a power-wheel in one end bight and support-wheels of greater diameter travelableupon lts ground run, a sprlngvopposed arm pivotally connected to the frame on which each support wheel is journaled the axes of the power-wheel and support-wheels being normally in substantially the samehorizontal plane.

WILLIAMl H. SMYTH. 

